A 40g radioactive material is placed in a chamber, having a half-life of 20 days. How much will be left after 80 days:
Correct answer: D. 2.5gm
- A. 40gm
- B. 20gm
- C. 5gm
- D. 2.5gm
Explanation
Correct. Here's the calculation:Calculate the number of half-lives:Total time elapsed = 80 daysHalf-life = 20 daysNumber of half-lives = 80 days / 20 days = 4 half-livesCalculate the remaining mass:After 1 half-life: 40g / 2 = 20gAfter 2 half-lives: 20g / 2 = 10gAfter 3 half-lives: 10g / 2 = 5gAfter 4 half-lives: 5g / 2 = 2.5gTherefore, 2.5g of the radioactive material will be left after 80 days.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Nuclear Physics
Atomic nuclei contain protons and neutrons, with nuclear size, mass defect and binding energy describing their stability. The work covers alpha, beta and gamma decay, decay equations, half-life and decay rate, along with radiation safety and medical applications such as imaging, radiotherapy and tracers.
Practise Nuclear Physics
1,254 free Nuclear Physics MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Nuclear Physics questions
When two negative beta particles are emitted from a nucleus, then the mass number:
The force responsible for binding the nucleus is:
For skin cancerous cells diagnostic, the radioisotopes used is
Which of the following electromagnetic radiation has the highest penetrating power?
The skin cancer can be caused by :
The number of neutrons in the nucleus of 92U235 is: